1. Field
The present invention relates to an organic light emitting display apparatus and a method of manufacturing an organic light emitting display apparatus.
2. Description of the Related Art
An organic light emitting display apparatus produces light in accordance with the following principle: when an electrical signal is applied to a cathode and an anode, holes injected from the anode move to a light emitting layer and electrons injected from the cathode move to the light emitting layer. Then, in the light emitting layer, holes and electrons are combined to form excitons, and the excitons change from an excited state to a ground state, thereby producing light.
Organic light emitting display apparatuses are considered as next-generation flat panel display apparatuses due to their wide viewing angles, high contrast ratios, and/or high response speeds. Specifically, active matrix (AM) organic light emitting display apparatuses (in which controls of emissions of pixels and degrees of the emissions are performed by using thin film transistors) have been actively researched.
However, in AM organic light emitting display apparatuses, thin film transistors for controlling each pixel are disposed under an organic light emitting device, and thus if a bottom emission-type organic light emitting display apparatus (in which light is emitted only toward a bottom substrate) is used, light is emitted only through portions where thin film transistors are not disposed, and thus an aperture ratio is decreased. Moreover, since a plurality of thin film transistors are used to control pixels, performance of an organic light emitting display apparatus may be poor.
To solve these problems, a top emission-type organic light emitting display apparatus (in which light is emitted away from the substrate) has been developed. However, since a top electrode, that is, an opposite electrode, of a top emission-type organic light emitting display apparatus needs to be a transparent electrode, the top emission-type organic light emitting display apparatus is thin and may have high resistance, causing an IR drop.
To prevent or protect from the IR drop, a low-resistance and conductive bus line may be connected to the opposite electrode. However, when this structure is applied in top emission-type organic light emitting display apparatuses, a contrast ratio may be lowered.